This invention relates to a process and apparatus for the compressive regeneration of flexible, porous materials typically employed as filter particles, oilseparating particles and/or carrier particles. These materials are loaded into a reactor along with substances to be removed from liquids such as water. Such substances are, for example, deposited solids, oil droplets and/or bacteria. After the particles become loaded with the above-discussed substances, they are conducted to a press chamber equipped with a press means for regeneration therein.
Filtration has long been one of the primary methods in the field of liquid and wastewater treatment for eliminating suspended solids from liquid streams. More recently, it has become known to employ as filter media, such materials as open-cell, porous members made of synthetic polymers, and in particular, foam materials as discussed in "Biological Fluidised Bed Treatment of Water and Wastewater" [1981], pages 272-283 P. F. Coope and B. Athinson. More particularly, the use of polyurethane foam is especially advantageous from the viewpoint of operation of the systems because of its high solids absorption capacity, resultant low pressure drop losses, high resistance to clogging, and its ability to eliminate large amounts of undissolved, organic dirt particles from liquid streams.
It is also known to employ polyurethane foam as a substrate material for bacteria required in biological activation processes conducted in wastewater treatment, as a coalescing medium in the removal of undissolved, liquid hydrocarbons from process waters and wastewaters, and in fermenting techniques.
However, since polyurethane particles employed in these systems eventually become loaded with the substances to be removed over the course of time, regeneration of the particles is necessary to maintain a high process efficiency. During regeneration, the materials which are retained inside the pores of the particles, such as deposited solids, oil droplets, or bacteria, must be removed therefrom to as complete an extent as possible, and must be separated from the material, i.e., polyurethane particles, as well as from any adhering water. After regeneration, the regenerated material must be returned to the reactor, e.g., in case of a cocurrent reactor the material is returned at the head, and in case of a countercurrent reactor the material is returned into the bottom zone. To achieve transportation to and from the reactor and regeneration zones, it is necessary to employ expensive auxiliary conveying devices such as mammoth pumps, conveying screws, conveyor belts, and other installations for transporting the polyurethane particles.